Intro to Flow and Mortar

Two awesome libraries by Square that I used to build SUPER (super.me).

Transcript

1. Flow and Mortar two awesome libraries by Square Thorben Primke www.super.me
 thorben@primke.com - @tprimke
2. Highlights • Background • Fragments vs Views • Flow / Mortar • Deep dive • Flow / Mortar Helpers
3. Jelly /SUPER • Jelly was built using Flow + Mortar • Made building a unique and animated UI • Discussed Fragments vs Flow + Mortar
4. Fragments vs Plain Views • Fragments and nested fragments • Complicated lifecycle • Suppose to make things easier and reusable • Be cautious checking if the state is valid whenever switching fragments • Can be clutted with both view and business logic
5. Flow • Used to describe screens and handle the navigation between them • Each screen is described by a state • Handles screen history • Handles saving the “screens” or paths into the Bundle
6. Flow • Flows can be extended to handle to nested / sub flows • Nested flows - Similar to nested Fragments when used to encapsulate a specific flow within an app. • Nested flows are better because a parents flow and inject data into the child flow such as the state during a compose flow
7. Mortar • Overlay on the application life cycle • Integrates with the Context’s getSystemService • Dependency injection • Provides global access to the persistence bundle • MortarScope
8. Mortar • BundleService - Any class has access to the Activity’s persistence bundle • Provides a Presenter / ViewPresenter • Integrates with Bundler • Can easily persist the Presenter data (onSave method)
9. Flow And Mortar Together • Screens all extend: Path • Each Screen in turn has its own Module (adds to Object Graph) • This module is added to a parent Module and its contents can be injected in the Presenter and View • Per MVP concept, both Presenter and View have an instance of one another • The View notifies the Presenter when it is ready • The injected Model is used by the Presenter to init the View
11. Setting up the MortarScope
12. Setting up the Activity
13. Flow Navigation • Provides navigation for setting / adding to the history • Provides back navigation in case there is more than one screen on the history stack
14. Screen Transitions • No default screen animations are provided • Flow’s PathContainer needs to be extended • Implement PathContainer’s performTraversal method
15. Mortar Flow Example’s SimplePathContainer
16. Flow History / State Persistence • Flow provides both the Flow and FlowDelegate classes • Flow holds the navigation history • Each Entry contains the Screen/Path object • FlowDelegate propagates a onSaveInstanceState call to the Flow which persists the history • Each Screen/Path is converted into a Parcelable object • Parcelable converter could serialize the Path into JSON
18. Subflow Hierarchy TopFlow ProfileScreen MainFlow ComposeFlow ComposeScreen RefineScreen - Adds ComposeState
20. Lifecycle Events • Sometimes its necessary to have access to onPause, onResume, onActivityResult • Examples: Sign on integrations, external resizing activity, custom Camera integration • Easy way - set explicit callbacks on *Your*Activity • Better - Manager that Presenters can register and unregister for lifecycle events
21. Lifecycle Events Activity LifecycleOwner ActivityLifecycleListener LifecycleViewPresenter ViewPresenter
24. Settings • Leverage injection to provide a setting to any class • Unique Annotation for each setting • Separate SettingsModule that is included in the RootModule • No SettingsManager needed and each settings value can be provided as needed
27. Less Repetitive Code
28. Good (and Bad) - No support for new Material style view animations - Both projects are still actively changing + Presenters could be tested + Mortar with Dagger make DI easy - Screen/Path’s modules (or components)
29. Questions? Thorben Primke www.super.me
 thorben@primke.com - @tprimke • Flow - https://github.com/square/flow • Mortar - https://github.com/square/mortar • Example - In the Mortar repo • Flow / Mortar Helpers - https://github.com/ thorbenprimke/flow-mortar-helpers